An estimated 250,000 people in the United States exhibit abnormally high secretion of parathyroid hormone, an 84-amino acid linear peptide which is involved in regulating the concentration of calcium ion in the plasma. The hormone apparently acts by regulating bone resorption and tubular reabasorption of calcium and phosphorus in the kidney. In primary hyperparathyroidism, tissue calcium storage is decreased, and bone demineralization results. Generally, hyperparathyroidism is the result of tumor formation in the parathyroid glands, four small egg-shaped glands closely associated with the thyroid.
The standard treatment for hyperparathyroidism is surgical removal of all abnormally enlarged glands. To do so successfully, however, requires that they be precisely located. They are notoriously difficult to locate, and even after surgery, symptoms may persist due to failure to remove hyperfunctioning parathyroid tissue completely.
While the approximate location of the parathyroids is presumed known, precise location is not established, and, further, these glands may be ectopic in various locations in the neck, throat and chest region. Therefore, an imaging technique which would permit the surgeon to establish the location of parathyroid tissue either in normal locations or ectopic placements is highly desirable. Such techniques are not presently available in the art.
Substances specific for parathyroid tissue are useful for development of such techniques. Antibodies, if properly chosen, shown the necessary specificity. Monoclonal antibodies reactive with parathyroid tissue have been used to modulate the secretory function (Posillico, J. T., et al, Clin Res (1985) 33:473A. However, these antibodies may not be suitable for imaging.